Fitting 1-D curve to data points, minimizing pre-defined error/loss function.
From wiki:
Curve fitting is the process of constructing a curve, or mathematical function, that has the best fit to a series of data points.
Questions tagged [curve-fitting]
3428 questions
9
votes
2 answers
Scipy sigmoid curve fitting
I have some data points and would like to find a fitting function, I guess a cumulative Gaussian sigmoid function would fit, but I don't really know how to realize that.
This is what I have right now:
import numpy as np
import pylab
from…
Johanna Köllner
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9
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1 answer
Bezier curve fitting with known end points
I want to fit a bezier curve with known end points (p0 and p3) to noisy 2d data. This seems like an easier problem than traditional 4-point bezier curve fitting but still too hard for me to figure out.
Can someone point me to existing code or an…
filip
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votes
1 answer
How to compute standard error from ODR results?
I use scipy.odr in order to make a fit with uncertainties on both x and y following this question Correct fitting with scipy curve_fit including errors in x?
After the fit I would like to compute the uncertainties on the parameters. Thus I look at…
Ger
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1 answer
geom_smooth and exponential fits
I am new to R and I'm having some difficulty plotting an exponential curve using ggplot2. I have a set of data below.
DATA
X Y x y
1 0.6168111 37.20637 0.6168111 37.20637
2 0.5478698 24.17084 0.5478698…
maherman
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votes
1 answer
Negative exponential fit: curve looks too high
I am trying to fit a negative exponential to some data in R, but the fitted line looks too high compared to the data, whereas the fit I get using Excel's built-in power fit looks more believable. Can someone tell me why? I've tried using the nls()…
ginko
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9
votes
1 answer
How to get error estimates for fit parameters in scipy.stats.gamma.fit?
I have some which I am fitting to the gamma distribution using scipy.stats. I am able to extract the shape, loc, and scale params and they look reasonable with the data ranges I expect.
My question is: is there a way to also get the errors in the…
iluvatar
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1 answer
Is there a way to plot a curve of best fit without function? Python
I need to plot a smooth curve of best fit but all the methods I've found use scipy.optimize.curve_fit(), and this requires knowing the function relating x and y. Is there a simpler way to do it for basic scatter plots?
What Im trying to get the…
harpreet bains
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9
votes
1 answer
Getting standard error associated with parameter estimates from scipy.optimize.curve_fit
I am using scipy.optimize.curve_fit to fit a curve to some data i have. The curves, for the most part, seem to fit very well. For some reason, pcov = inf when i print it off.
What i really need is to calculate the error associated with the…
user3282375
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2 answers
How to visualize a nonlinear relationship in a scatter plot
I want to visually explore the relationship between two variables. The functional form of the relationship is not visible in dense scatter plots like this:
How can I add a lowess smooth to the scatter plot in Python?
Or do you have any other…
tobip
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9
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1 answer
What are the weight values to use in numpy polyfit and what is the error of the fit
I'm trying to do a linear fit to some data in numpy.
Ex (where w is the number of samples I have for that value, i.e. for the point (x=0, y=0) I only have 1 measurement and the value of that measurement is 2.2, but for the point (1,1) I have 2…
jbssm
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9
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5 answers
Pass tuple as input argument for scipy.optimize.curve_fit
I have the following code:
import numpy as np
from scipy.optimize import curve_fit
def func(x, p): return p[0] + p[1] + x
popt, pcov = curve_fit(func, np.arange(10), np.arange(10), p0=(0, 0))
It will raise TypeError: func() takes exactly 2…
Yuxiang Wang
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9
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7 answers
Plot digitization - scraping sample values from an image of a graph
This isn't really "OCR", since it's not recognizing characters, but it's the same idea applied to curves. Anyone know of an image-processing library or established algorithm for retrieving the values from a (raster) plot image? For instance, in…
endolith
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9
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4 answers
How to make a curve smoothing in matlab?
the blue plot is a noisy plot of the original plot(red). Is there any way to approximate the blue plot to nearly red plot?
crack_addict
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2 answers
Linear regression - reduce degrees of freedom
I have a Pandas dataframe with columns like
Order Balance Profit cum (%)
I'm doing a linear regression
model_profit_tr = pd.ols(y=df_closed['Profit cum (%)'], x=df_closed['Order'])
The problem with this is that standard model is like…
Femto Trader
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9
votes
7 answers
How to fit the 2D scatter data with a line with C++
I used to work with MATLAB, and for the question I raised I can use p = polyfit(x,y,1) to estimate the best fit line for the scatter data in a plate. I was wondering which resources I can rely on to implement the line fitting algorithm with C++. I…
feelfree
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